This invention relates to a method and apparatus for transferring a predetermined graphic image, cut from a thin flexible layer of sign making material and adhesively attached to a carrier sheet, onto the supporting surface of a sign or graphic display.
Well known in to the art, a common method for the production of signs, and other graphic displays, employs the use of a sign making material. This material is a two ply laminated web comprised of a first ply of a thin flexible layer or sheet of vinyl, and a second ply of a base layer, carrier sheet or release paper, with the two layers being separated by a thin layer of permanently tacky or pressure sensitive adhesive. The carrier sheet, or release paper, is specially coated to prevent strong adhesion of the vinyl. Vinyl is commonly available in rolls of varying width and length. Although an image may be cut by hand or die-cut, most are cut by computer controlled plotters or cutters. The cutter is designed to precisely cut the outline of the graphic image or images completely through the first ply and stop short of cutting through the second ply. When cutting is complete, the area of the first ply surrounding the graphic is removed or weeded away, leaving the desired graphic attached to the second ply.
The graphic image is then ready for transfer to the surface where it will be permanently displayed. Most often the transfer of the graphic image to the display surface or substrate employs the use of a transparent or semi-transparent tape. The tape may be paper, plastic, or other sheet material which is coated with an adhesive on it""s underside. The adhesive is designed to fracture at a higher stress than the bond between the first ply and the second ply of the sign making material and at a lower stress than the bond between the first ply of the sign making material and the substrate.
Transfer tape is commonly available in rolls of varying width and length. A piece of tape sufficient in size to cover the entire area of the first ply containing graphics is employed to transfer all of the graphic image at once. In this manner the various parts of the graphic image will retain their position relative to each other during transfer.
The most common method for transferring the graphics is a manual process. Typically vinyl and transfer tape are stocked in complementary widths dictated by the capacity of the cutter. Work tables are generally arranged with, at one end, a support for the roll of transfer tape that will allow the material to be pulled or spooled from the roll in a plane above and parallel to the work surface. The adhesive face of the transfer tape is oriented to contact the table surface.
The weeded graphic is placed on the table with the finished face of the vinyl facing up. It is positioned to be directly under the transfer tape as the transfer tape is spooled from the roll. The transfer tape is spooled from the roll and is not allowed to touch the weeded graphic until the transfer tape is of sufficient length to completely cover the graphic. The tape is then laid down incrementally to insure smooth application. Once the transfer tape is in position it is cut from the roll and pressed firmly down on the graphic with a hand held roller or squeegee to insure adhesion. The lamination of release paper, vinyl and transfer tape is then oriented or registered on the substrate relative to it""s permanent position. One edge of the lamination is temporarily taped to the substrate to maintain registration and acts as a hinge which allows the lamination to flip over exposing the back of the release paper. The release paper, having a lesser bond with the vinyl than the vinyl with the transfer tape is peeled away leaving the vinyl attached to the transfer tape and the adhesive face of both exposed. Supporting the remaining lamination so that it can be laid down evenly, the lamination is flipped back bringing the adhesive face of the vinyl and transfer tape in contact with the substrate. Once the lamination is in position it is pressed firmly down on the graphic with a hand held roller or squeegee to insure adhesion. The transfer tape having a lesser bond with the vinyl than the vinyl with the substrate is peeled away leaving the vinyl graphic adhered to the substrate. The transfer tape is discarded. This process is repeated for each individual color used to produce the final sign or display.
The difficulties associated with the above mentioned process are well known in the industry:
a) The transfer of vinyl graphics is a multi-step process requiring the skilled manipulation of various flexible sheet goods having exposed adhesive surfaces. The material must be maintained in a planer orientation, contact must be controlled, and placement somewhat precise. In instances where the graphic to be applied is relatively large, more than one person may be required to control the material. Improper manipulation can result in misalignment, permanent wrinkling of the finished product, air trapped between laminations causing bubbles, or complete deformation of the graphic rendering the product unusable.
b) Because the transfer tape is constructed of a flexible sheet material with an adhesive face, it is difficult to remove after application in a reusable manner. Although the adhesive properties may still be intact, the labor involved in maintaining the tape in a planer, unwrinkled, and clean condition is generally not worth the effort. Therefore the expense of application tape is incurred with each transfer. Additionally there is the expense of handling and proper disposal of waste, consumption of nonrenewable resources, and increased volume to area landfills.
c) Proper orientation of the graphic on the substrate is generally visual as this is the nature of the product. A trained eye is required to efficiently place graphics without the aid of measuring instruments, whereby use of such instruments, increase the time consumed in producing the finished product. When positioning the lamination of release paper, graphic, and transfer tape on a substrate, the opaque release paper covers a substantial portion if not all of the substrate limiting visual reference. When additional layers of vinyl must be applied to achieve a multicolor product, the opaque release paper impedes visual reference to the previously applied layers.
U.S. Pat. No. 5,352,314 (1994) to Coplan includes an open rectangular frame covered on one side with application tape used to transfer the graphic. The adhesive face of the tape is positioned toward the frame, stretched tight and clipped in place on each attached end. The frame is laid over the weeded graphic with the adhesive face of the application tape suspended just above the lamination. The clear film allows visual alignment and when in position the film is pressed down onto the graphic with a hand held roller or squeegee. The frame is then lifted to access the lamination now attached to the application tape. The release paper is removed from the graphic leaving the graphic attached to the application tape, with the adhesive side of both the graphic and application tape exposed. The frame is then positioned over the substrate, aligned, and pressed down onto the substrate with a hand held roller or squeegee. The frame is lifted to access the lamination now attached to the application tape. The substrate with the graphic attached is removed from the application tape.
Although obvious advantages exist with U.S. Pat. No. 5,352,314 (1994) to Coplan, they are limited to the planer control of the application tape, reuse of the application tape, and orientation of the graphic. The invention does not automate or substantially reduce the number of steps required by the process previously described. Additionally it is difficult to separate the substrate and applied graphic from the application tape after the transfer is complete. With both being held substantially planer, the finished product must be pried from the tape. This stretches the tape and requires constant re-tensioning.
A method for the planer control of the transfer tape and graphic is demonstrated in U.S. Pat. No. 5,795,435 (1998) to Waters.
U.S. Pat. No. 6,102,096 (2000) to Johansson demonstrates a method for the planer control of the transfer tape and graphic and a method of adhering same.
The invention resides in a machine, and method of use for the transfer of a substantially planer article, shape, graphic image, or plurality thereof, from a carrier sheet, to which it is adhesively attached, to another means of support. The invention is well suited for use in the graphic sign industry for the application of vinyl sign making materials, but it""s use is not necessarily restricted to this application as almost any flexible thin gauge material that can be arranged and adhesively attached to a receiving surface, may be transferred.
The device according to the invention is characterized in that a roller attached to a means of traverse is moveable in a reciprocating manner across a substantially planer and unyielding support surface. The roller, substantially spanning the width of the support surface, is made to contact the support surface with pressure and controlled in a manner as to lay down a transfer web.
The web is constructed of a flexible sheet material with an adhesive coating applied to one side. The base sheet of the transfer web is of sufficient strength that it may be held in tension when laid down and peeled up without excessive deformation. The web is held stationary at one end of the traverse and passes in front of and around the roller. The opposite end of the web is free to be pulled with the roller while held in tension and is of sufficient length to be laid down the entire length of the traverse while remaining attached to the tensioning device.
The method according to the invention includes the reciprocating motion of the roller over the length of the traverse, laying down and peeling up the transfer web. The article to be transferred is placed on the support surface relative to it""s final position on the receiving surface. The carrier sheet is placed in contact with the support surface. The roller is then made to traverse the length of the support surface, sandwiching the article and the carrier sheet between the adhesive face of the transfer web and the support surface. The adhesive on the transfer web is of such composition that with sufficient pressure from the roller it will bond to the article at a higher strength to fracture than the bond between the article and the carrier. With the reverse of the roller, the transfer web is pulled back by the tension device and due to the differential bonding, the article is lifted away from the carrier sheet. The position of the article is maintained relative to both its original alignment on the carrier sheet and placement on the support surface. The carrier sheet is removed and replaced with the receiving substrate having it""s finished face opposite the support surface and aligned relative to the previous placement of the article. The roller is then made to traverse the length of the support surface, sandwiching the article and the receiving substrate between the adhesive face of the transfer web and the support surface. The adhesive on the transfer web is of such composition that with sufficient pressure from the roller the article will bond to the receiving substrate at a higher strength to fracture than the bond between the article and the transfer web. With the reverse of the roller, the transfer web is pulled back by the tension device and due to the differential bonding the article remains attached to the receiving substrate.
The invention serves the need for one device that will separate the graphic from the carrier and reapply it to the substrate. The advantage over prior art is as follows:
a) The number of steps required to transfer graphic images by conventional means are substantially reduced, simplifying the process and saving time. Positioning and bonding of the transfer medium is controlled by the invention and accomplished simultaneously, nearly eliminating wrinkles and bubbles.
b) The transfer medium is maintained in a controlled manner by the invention eliminating manual handling during the transfer process. This prevents deformation of the base sheet and allows the transfer medium to be used a plurality of times based on it""s ability to properly adhere.
c) The transfer medium is controlled in a manner such that it""s position relative to the support surface remains constant. Thereby a graphic stripped from the release paper will be applied in the same position relative to the support surface. This provides a means to position the graphic, absent the receiving substrate. The support surface may then be made translucent and backlit, reducing the opacity of the release paper. With alignment markings in the support surface being visible, position of the receiving substrate may be assumed. Registration marks placed on the graphic at the time of design and cutting provide alignment to the grid of the support surface.